The invention relates to fiber optic coupling devices such as those used in networking and telecommunications equipment. More particularly, the invention relates to coupling devices that provide an imbedded capability to receive optical signals and convert these signals to electrical signals and/or receive electrical signals and convert said signals for transmission as optical signals.
As is known, the use of optical fiber has gained wide acceptance for use in such applications as telecommunications, networking, computing and general electronics. This is due to its numerous advantages including a relatively low cost of manufacture, excellent mechanical reliability and EMI (Electro-Magnetic Interference) characteristics and most importantly, that it provides a significant increase in information transmission bandwidth over copper wire. To make effective use of optical fiber, devices for the transmission, re-transmission and receipt of signals are used. These devices have taken many forms, but have traditionally consisted of a component which secures and aligns the optical fibers with a laser or other light-emitting device for the transmission of signals and/or an optical sensor for the receipt of signals. Signals to be transmitted typically are converted from an electrical signal generated by another device into an optical signal. Conversely, received optical signals are converted into electrical signals for processing by other electronic devices. Traditionally, this conversion of signals has been performed by an electronic component which is physically separate from that which secures and aligns the optical fibers.
However, given current trends toward miniaturization and lowering the power consumption of electronic components, it is understandable that, whenever possible, components must perform multiple functions. The present invention achieves these goals of miniaturization and having components with multiple functions by forming circuitry on the components which secure and align the optical fibers such that electronic devices (e.g. integrated circuits) can be mounted directly on these components and can be electrically connected to them. There are several known methods and apparatus for coupling optical fibers as described in the following U.S. Letters Patents:
U.S. Pat. No. 4,625,333xe2x80x94Takezawa et al
U.S. Pat. No. 5,005,939xe2x80x94Arvanitakis et al
U.S. Pat. No. 5,109,454xe2x80x94Okuno et al
U.S. Pat. No. 5,123,074xe2x80x94Yokota et al
U.S. Pat. No. 5,241,614xe2x80x94Ecker et al
U.S. Pat. No. 5,475,778xe2x80x94Webb
U.S. Pat. No. 5,515,468xe2x80x94DeAndrea et al
U.S. Pat. No. 5,535,296xe2x80x94Uchida
U.S. Pat. No. 5,604,831xe2x80x94Dittman et al
U.S. Pat. No. 5,687,267xe2x80x94Uchida
U.S. Pat. No. 5,781,682xe2x80x94Cohen et al
U.S. Pat. No. 4,625,333 describes a device whereby lenses are utilized to focus the light from a light-emitting module onto a transmission optical fiber, and from a reception optical fiber onto a light receiving element. This device is directed toward providing support for a single transmission optical fiber, and a single reception optical fiber.
U.S. Pat. No. 5,005,939 is assigned to the same assignee as the present invention and is incorporated herein by reference. U.S. Pat. No. 5,005,939 describes an assembly in which optical fibers are aligned with a pair of opto-electronic devices. One of the opto-electronic devices acts as a transmitter and the other as a receiver. The opto-electronic devices are electrically connected to semiconductor chips which reside on a ceramic substrate that is separate and distinct from the opto-electronic devices.
U.S. Pat. No. 5,109,454 describes an apparatus for light communication in which photo-connector receptacles containing optical elements are electrically connected to peripheral circuits. The peripheral circuits and the optical elements are mounted on separate and distinct surfaces. The peripheral circuits are electrically connected to terminals which can be used to form an electrical connection to a circuit that is external to the apparatus. The preferred embodiment of the apparatus describes two (2) photo-connector receptacles.
U.S. Pat. No. 5,123,074 describes an insulating substrate with electrical circuits formed on a surface thereof that is adapted for having optical and electric circuit components mounted thereon. U.S. Pat. No. 5,123,074 describes the substrate and a method for manufacturing same.
U.S. Pat. No. 5,241,614 is assigned to the same assignee as the present invention and is incorporated herein by reference. U.S. Pat. No. 5,241,614 describes an optical fiber interface and a method for manufacturing same. The optical fiber interface utilizes a block with V-grooves to secure optical fibers and align these with a detector on a receiver chip as well as a coupling lens which is aligned with a laser chip located on an optical transmitter carrier. Both the detector on the receiver chip as well as the coupling lens and laser chip on the optical transmitter carrier are oriented at right angles to the axes of the optical fibers with which these are aligned. The ends of the optical fibers are ground at an angle and metalized to produce angled fiber end faces. The angled fiber end faces reflect light and establish optical connectivity between the optical fibers and both the detector and the coupling lens.
U.S. Pat. No. 5,475,778 describes a connector that sends and receives optical signals over optical fibers. This connector has a transducer which converts incoming optical signals to electrical signals as well as an additional, independent transducer which converts outgoing electrical signals to optical signals. Both transducers are electrically connected to a microprocessor, which is in turn electrically connected to a surface mount device which contains circuitry that is required for the functioning of the connector. Collectively, the microprocessor and the surface mount device comprise an electrical processing circuit for processing the electrical signals associated with the transmitted and received optical signals. The transducers, the microprocessor, and the surface mount device are all mounted on a common substrate.
U.S. Pat. No. 5,515,468 describes a device that optically connects a fiber optic transmission line to an opto-electronic device mounted on a substrate. The light transmission axis of the fiber optic transmission line is substantially not coincidental with the operative axis of the opto-electronic device. Consequently, a light bending sub-component, comprised of lenses and a reflecting surface, is required to optically connect the fiber optic transmission line to the opto-electronic device. The preferred embodiment of this device describes both a simplex and a duplex embodiment. The simplex embodiment provides support for a single fiber optic transmission line, and the duplex embodiment provides support for two (2) fiber optic transmission lines.
U.S. Pat. No. 5,535,296 describes a mounting assembly that supports optical fibers between a grooved substrate and a clamping substrate. The optical fibers are aligned with an opto-electronic device (e.g. a laser diode) that is mounted on a substrate which is separate and distinct from both the grooved substrate and the clamping substrate. Alignment between the optical fibers and the opto-electronic device is achieved through the use of pre-set reference marks on the substrate to which the opto-electronic device is attached. The mounting assembly can be configured to contain either a photodetector receiver array or an edge emitting laser diode transmitter array.
U.S. Pat. No. 5,687,267 is a continuation of U.S. Pat. No. 5,535,296, but is instead directed to an optoelectronic package.
U.S. Pat. No. 5,604,831 is assigned to the same assignee as the present invention and is incorporated herein by reference. U.S. Pat. No. 5,604,831 describes an optical module with flexible circuit boards that are used to electrically connect optical transceiver sub-assemblies to electronic circuits on a separate and distinct ceramic substrate within the module. The flexible circuit boards are soldered to the electronic circuits on the ceramic substrate using a fluxless solder in an atmosphere of formic acid mixed with nitrogen. Solder reflow is performed using a laser.
U.S. Pat. No. 5,781,682 is assigned to the same assignee, among others, as the present invention and is incorporated herein by reference. U.S. Pat. No. 5,781,682 describes an optical coupling apparatus for attaching a connector at the end of an optical cable to a receiver or transmitter array contained within a connector shell. The optical cable, the connector at its end, and the receiver or transmitter array within the connector shell are all provided in a parallel format such that multiple optical connections can be established. Optical fibers in the optical cable and active elements of the receiver or transmitter array are at right angles to each other. Optical connectivity between the optical fibers and the active elements is realized through the use of an array of reflecting fins so as to effect a 90 degree bend in the light path. The ends of the optical fibers and the reflecting fins are contained in the connector which is separate from the connector shell that contains the receiver or transmitter array. A connector shell can be configured to contain either a receiver or a transmitter array.
It is believed, therefore, that an optical coupler which provides the many advantages taught herein would constitute a significant advancement in the art.
It is a primary object of the present invention to provide an optical coupler that is of simplified construction compared to many known devices.
It is another object of the invention to provide an optical coupler that has a reduced cost of manufacture.
It is yet another object of the invention to provide an optical coupler of miniaturized construction compared to many known couplers.
It is yet another object of the invention to provide an optical coupler that consumes relatively less electrical power than many known such couplers.
It is yet another object of the invention to provide an optical coupler with improved performance.
In accordance with one embodiment of the invention, there is provided an optical coupler which comprises a housing for positioning at least one optical fiber having an axis within the housing, circuitry positioned on or within the housing, an integrated circuit positioned on or within the housing that is electrically connected to the circuitry on or within the housing using a plurality of electrical conductors and aligned with the axis of the at least one optical fiber having an axis within the housing.
In accordance with another embodiment of the invention, there is provided a method for making an optical coupler wherein the method comprises the steps of providing a housing, positioning at least one optical fiber having an axis within the housing, forming circuitry on or within the housing, positioning a plurality of electrical conductors on an integrated circuit and positioning the plurality of electrical conductors and the integrated circuit on or within the housing such that the integrated circuit is electrically connected to the circuitry on or within the housing and aligned with the axis of the at least one optical fiber having an axis within the housing.